The Health Insurance Portability and Accountability Act, or HIPAA, was passed on July 1, 1997. While this act involves many aspects of health care, it has had a profound effect on the availability of health care in the United States. Thanks to HIPAA, there are rules limiting the maximum length of time a pre-existing exclusion can be applied in a group plan, and there are even ways in which you can reduce or eliminate this exclusion period altogether. Under the HIPAA guidelines, the maximum amount of time that you have to wait in order to get coverage for your pre-existing condition cannot exceed 12 months, or 18 months for late enrollees.

A year is a long time to wait for medical coverage, so HIPAA uses what is known as "credible coverage." This term refers to any health insurance you had before your new insurance plan, as long as it was not interrupted by a period of 63 or more days. This time period can be longer, depending on your state laws and the type of insurance plan you were on. Once you have proven that you have had uninterrupted insurance before your current plan, this insurance coverage can be credited toward any pre-existing condition exclusion you may have. In fact, if you had at least one year of group health insurance at one job and then received health insurance at a new job without a break of more than 63 days, the new health insurance plan cannot impose a pre-existing condition exclusion on you at all. If however, a break in coverage is greater than 63 days, all the health insurance coverage before the break is not counted toward your pre-existing condition exclusion period.

HIPAA placed limitations on the pre-existing condition exclusion -- and it also helps ensure that those with pre-existing conditions can get health care at all. So, you might have to live with a pre-existing condition exclusion period, but you can't be denied coverage in a group plan because of your health. In fact, not only does the plan have to cover you regardless of your health, it also can't charge you more than a co-worker who may be in perfect shape.

Hidden Pre-Existing Condition Exclusions

When an insurance plan does not officially label a certain condition as a pre-existing condition but essentially treats it like one, it's known as a hidden pre-existing condition exclusion. Under HIPAA regulations, they are not permitted in group health plans, but they could still occur in individual health insurance plans and some noncompliant group plans.

Common examples of these types of exclusions include:

­­Denying medical coverage to treat injuries resulting from an accidental injury that occurred before the plan began.

Not covering a congenital medical condition when that same condition is covered when not deemed congenital.